Low volts & low engine temp - thoughts?

[Rhod]

Hi all

This is the scenario:
I have a digital voltmeter linked plugged in via the cigarette lighter, which reads about 0.5V less than a true reading across the battery terminals.

I installed a new 90AH battery on Saturday, to replace the 62AH one which I felt might be contributing to starting problems. All seemed fine & the dashboard voltmeter showed 13.8-14.1V as normal.

Driving back over to the West last night everything seemed normal. I stopped for a pee, leaving the engine running, & on pulling away noted that the voltmeter reading had gone down to 12.2V (No accessories or heater fan on, but main beams). Pulled in after a few miles & checked the alternator belts - everything normal there. Afeter another few miles I noticed that the temperature gauge was sitting at 12 o'clock instead of it's usual 1o'clock (Mason modification fitted). Thinking that the cooling fans might have come on & somehow stuck on, thus consuming battery power. Stopped again & pulled all 3 fan fuses plus checked voltage at battery with a meter I was carrying (12.8V with all lights etc off) - terminals tight. Running again, the dashmeter showed 12.2V, so battery probably being slowly depleted, but pulling the fan fuses had no effect on either volt or temp readings.

Pending a check on the alternator output directly tonight (just incase the battery is dodgy), I'm assuming that the alternator is on it's way out (seems to match with the factsheet analysis), but I'm at a cpmplete loss to explain the effect on the engine temperature gauge! Maybe just coincidence? Does anyone have any thoughts on why the gauge should drop it's reading like this I haven't had a chance to check for a loose earth connection on thegauge yet, but doubt if this is the cause, since the reading remained steady. Unfortunately I can't say for certain wheher the gauge climbed to it's usual 1 o'clock position & then dropped back, or never got past 12 o'clock.

All revelations greatly appreciated.

Rhod

[Aethelric]

My lighter socket is connected to the leisure battery, along with everthing else on that circuit. To tell the truth I'm not sure what - but certainly the internal lights and the radio.
I tried running an inverter off it last week. As soon as I put it under load (about 20 watts) the low voltage alarm started sounding on the inverter. I think it comes on around 11V. (the inverter works fine when connected straight across the battery).
I probably had the internal lights on as well.
So there seems to be a sizable resistance in the path between the battery and the lighter socket and current to the inside lights is flowing in that path too. This may account for some of your measurements.
Maybe the mason alarm is susceptable to the reduced voltage too.
Dave

[dandywarhol]

I think the cigar lighter wiring is just a bit on the light side to be suitable for invertors/coolboxes etc. I've rewired my rear one with a heavier cable.
The Mason alarm does seem to be very voltage sensitive - the reading drops on mine if the battery isn't being charged. still a small price to pay methinks.........

[Aethelric]

I think the cigar lighter wiring is just a bit on the light side to be suitable for invertors/coolboxes etc. I've rewired my rear one with a heavier cable.
The Mason alarm does seem to be very voltage sensitive - the reading drops on mine if the battery isn't being charged. still a small price to pay methinks.........

I think you are right about the cigar lighter wiring. When I need the inverter, I put it under the bonnet, connect it directly to the battery, and plug it into the rcd. The cigar lighter is fine for charging phones, satnav. bluetooth, etc.

[Rhod]

Dandy wrote

The Mason alarm does seem to be very voltage sensitive - the reading drops on mine if the battery isn't being charged. still a small price to pay methinks.........

Thanks Dandy - dying alternators I can cope with, but the thought of trying to trace a fault with the temperature gauge was starting to depress me ! I did wonder if it could be affected by the battery voltage, but thought that I was just being hopeful. Will confirm if a new alternator sorts it out.

I'm glad I fitted the voltmeter (spurred by a similar experience on the BeeEmm ), since I wouldn't have known there was a problem otherwise - until left stranded some cold wet night. However IF the Mason alarm is noticeably affected by a reduction in charging, then this could be a useful side-effect of fitting the modification...
Rhod

[dandywarhol]

Might be worth hdropping Dave Mason a line for his opinion - he' a member here.

[Rhod]

Was thinking of getting in touch with Dave, but will confirm that alternator has gone first.

Just looked at alternator prices:
Reconditioned unit from Bongo Shop = £245 incl VAT
New(?) unit from AVA = £225 incl VAT
New unit from Bongo Bits = £187.59 incl VAT

Im confused since I always thought that a recon unit should be cheaper than buying new. Can anyone see a good reason for not going with the BB item? - like has anyone heard of problems with these units. They must be cheaper for a reason......

Rhod

[phil 1]

Hi
I replaced mine last year with one from bongobits and they are not genuine Mazda units. The first one i received screamed and smoke pored out of it as soon as i started the engine but to be fair bongobits replaced it no problem. The one i have now works fine but the wiring loom is in a different position right on top of the dipstick. you have to push the dipstick to one side to check the oil and the last time i checked the oil i snapped the top of the dipstick of trying to remove it:( and the bottom bracket needed a packer behind it.
Had i known this when i ordered i would have gone for a reconditioned unit.
hope this helps
Phil

[Rhod]

Cheers Phil
My dipstick's already broken , but it sounds as if the extra money might be worth it in the long term. The factsheet talks about £180 for a recon unit from another source though, so I'll make enquiries there too. First thing is to double-check it's not a dud cell in the new battery or something similar. 11pm after a 3hr drive on tenterhooks was not the time to do that detail of check
Rhod

[Dave Mason]

Dandy wrote

The Mason alarm does seem to be very voltage sensitive - the reading drops on mine if the battery isn't being charged. still a small price to pay methinks.........

Thanks Dandy - dying alternators I can cope with, but the thought of trying to trace a fault with the temperature gauge was starting to depress me ! I did wonder if it could be affected by the battery voltage, but thought that I was just being hopeful. Will confirm if a new alternator sorts it out.

I'm glad I fitted the voltmeter (spurred by a similar experience on the BeeEmm ), since I wouldn't have known there was a problem otherwise - until left stranded some cold wet night. However IF the Mason alarm is noticeably affected by a reduction in charging, then this could be a useful side-effect of fitting the modification...
Rhod

I own a Townace and have never touched a Bongo so I can't give a definite comment. I was able to produce the Bongo Mason alarm, with help from a couple of Bongo owners, because the Bongo temp gauge works similarly to the Toyota ones.

I think that the supply voltage directly affects the temp gauge reading but not when its in the "normal" dead zone without a Mason alarm fitted. Possibly one of the reasons the gauge was designed that way, so the "normal" position wasn't affected by the supply voltage.

With a Mason alarm the gauge reading will therefore be noticeably affected by supply voltage and if the reading is close to where you've set the alarm it will affect that too. However the supply voltage should not be changing so, yes, perhaps this does turn out to be a useful side-effect - flagging up a bad connection, failing battery or charging system.

[dandywarhol]

Anyone know if there's a voltage stabalizer for the temp and fuel gauges on the Bongo?

[Rhod]

What a great resource this forum is
Within 30 mins of getting home I'd 90% diagnosed the problem, thanks to the Factsheet. By lunchtime the following day Dandy had confirmed that the reduced temperature reading might actually be related to low voltage. By the next day the new alternator was in the post! Many thanks to all concerned

Two useful bits of information to come out of this:
1) With normal charging service resumed, the temperature gauge is back to normal behaviour. So if you don't have a voltmeter wired in & your temperature gauge (Mason modification fitted) suddenly drops to read 12 o'clock, then it would seem a good indication that either your alternator is failing, or that your voltage is failing for some other reason. As confirmed by Dave Mason above.

2) After checking other sources of a replacement alternator, I followed the factsheets recommendation & contacted Nippon Distribution. A reconditioned Bongo alternator arrived in 2 days (would be next day in areas not classed as "island" & before 10am for a small premium). The alternator was a straight replacement - unlike the Bongo Bits item as reported by Phil1 on this thread. Cost was £130 plus VAT, plus carriage - very competitive. This price assumes an exchange unit - it's another £100 if you don't send your old one back.

Rhod

[Alex86]

my temp gauge reads 11 o'clock not 12 or 1???

Is This Bad?

[corblimey]

No that's not bad, that's exactly as it should read if you don't have a Mason alarm fitted.

The Mason alarm increases the sensitivity of the gauge and in doing so moves the normal gauge position from 11 o'clock to 1 o'clock. The alarm also provides yet another beep if the engine starts to get a bit too warm.

[waycar8]

hmmn, what an interesting thread, .....................

took the masons alarm out of my old bongo and put it my new one a couple of months backs, in my old one it read 1 oclock most of the time, fluctuating when driving and stood at lights ect.

but in my new bongo it reads 12 oclock most of the time , and goes up to 1 oclock when the engine was getting a bit of a push when going up hills ect then settling back at 12 oclock, i bled the system a few times changed the temp sendor and thermostat, i just presumed it was just this bongos fans being more effecient (even thoe cant say ever heard them come on )